Question

Jemima is making a paper tepee, as shown below.
What is the area of the paper required to make the lateral surface of the tepee?

238.8 cm2

1131.1 cm2

1256.8 cm2

565.7 cm2

Answer 1

What equation did you use?

Answer 2

oh mixed two formulas my bad

Answer 3

\[\pi r \sqrt{r^2 + h^2}\]

That is the equation for the lateral surface area

Answer 4

Not sure how to derive it but it looks right....My first thought was to multiply 2*pi*r with the height

but that gives u the lateral surface area of a cylinder.

Answer 5

i still didnt get any of those answers

Answer 6

@KingGeorge can you help?

Answer 7

I did get one of the answers. The 20 is not the height you have to solve for the height

Answer 8

i know^

Answer 9

I believe the formula romero gave is correct. It's simpler if you use \(\sqrt{r^r+h^2}=s\) though. This gives you the formula \(\pi r s\) where \(r\) is the radius, and \(s\) is the side length which is 20.

Can you tell me what the radius is?

Answer 10

the height should be 18^2 + 20^2 = c^2
324+400 = c^2
724 = c^2
26.907248 is the height, correct?

Answer 11

no
18^2 +c^2 = 20^2

Answer 12

Just ignore that for now. All you need to know is that \(\sqrt{r^2+h^2}=20\).

Answer 13

20 is the hypotenuse

Answer 14

oh i switched it... :/ now i got it^

Answer 15

ok @KingGeorge

Answer 16

(3.14)(9)(20) = 565.2 but thats still not one of the above answers....

Answer 17

If you plug in pi instead of 3.14 you get a value closer to 565.7

Answer 18

If you use \(\pi\approx22/7\) you will get 565.7

Answer 19

oh ok.... i always got told to just plug 3.14 for pi

Answer 20

That's an estimated value for pi.

Answer 21

^yeah i know @romero
thanks guys :D

Answer 22

You're welcome.

Answer 23

Medals for everyone!!!! Yay!!

Answer 24

^lol :)

Answer 25

Medals all around!